多边形钢厚板钢桥多焊缝焊接残余应力分析

Analysis of welding residual stress of polygonal thick steel plate of steel bridge with multiple welds

为研究大型钢桥塔现场焊接应力应变情况,基于热弹-塑性理论、采用热-力完全耦合分析方法,应用ABAQUS软件结合Fortran语言编辑球形热源程序,对大型不规则桥塔多焊缝焊接的温度场和应力场进行了数值模拟。获得了焊接温度场和构件应力应变的动态变化过程,结果表明:热源前方温度急剧下降,梯度较大,后方温度下降比较缓和,梯度较小。焊接热源横向温度变化较迅速,焊接冷却完成后转角处热量比较集中;焊接侧板呈现中间小两边大的规律,在边界约束处达到最大值,呈U型分布;垂直焊缝方向的残余应力在构件表面残余应力呈W型,内部呈M型;焊接过程变形和移动热源类似,冷却完成后侧边横向位移变形由热源两侧向热源中心聚拢,在热源中心与边界距离的中线处达到变形最大值,焊接热源和两侧固定端变形约为零,呈正弦型规律分布。研究结果可为大型钢桥塔焊接残余应力、变形的调控,以及焊接工艺的优化提供依据。

In order to study the field welding stress-strain situation of large steel bridge towers,based on the thermoelastic-plastic theory,the use of thermal-force fully coupled analysis method,the application of ABAQUS software combined with Fortran language editor spherical heat source program,the temperature field and stress field of large irregular bridge tower multi-weld welding numerical simulation.The dynamic change process of the welding temperature field and component stress-strain was obtained,and the results showed that the temperature in front of the heat source drops sharply with a large gradient,while the temperature at the back drops more gently with a smaller gradient.More rapid changes in the lateral temperature of the welding heat source and more concentrated heat at the corners after the welding cooling is completed.The welded side plates show a pattern of small in the middle and large on both sides,reaching a maximum at the boundary constraint with a U-shaped distribution.Residual stresses in the direction of the vertical weld are W-shaped on the surface of the member and M-shaped internally.Welding process deformation and mobile heat source is similar,after the completion of cooling lateral displacement deformation from both sides of the heat source to the center of the heat source gathered in the center of the heat source and the boundary distance between the midline to reach the maximum deformation,welding heat source and both sides of the fixed end deformation is about zero,a sinusoidal regular distribution.The results of the study can provide a basis for the regulation of residual stress and deformation of large steel bridge tower welding,as well as the optimization of the welding process.